Buzalewicz Igor, Karwańska Magdalena, Wieliczko Alina, Podbielska Halina
Bio-Optics Group, Department of Biomedical Engineering, Wroclaw University of Science and Technology, 27 Wybrzeze S. Wyspianskiego St., 50-370, Wroclaw, Poland.
Department of Epizootiology and Veterinary Administration with Clinic of Infectious Diseases, Wroclaw University of Environmental and Life Science, 45 Grunwaldzki Square, 50-366, Wroclaw, Poland.
Biosens Bioelectron. 2021 Jan 15;172:112761. doi: 10.1016/j.bios.2020.112761. Epub 2020 Oct 24.
The development of new diagnostics techniques and modalities is critical for early detection of microbial contamination. In this study, the novel integrated system for multi-parametric optical phenotyping and characterization of bacterial colonies, is presented. The system combines Mach-Zehnder interferometer with a spectral imaging system for capturing multispectral diffraction patterns and multispectral two-dimensional transmission maps of bacterial colonies, along with the simultaneous interferometric profilometry. The herein presented investigation was carried out on five representative bacteria species and nearly 3000 registered multispectral optical signatures. The interferograms were analyzed by four-step phase shift algorithm to reconstruct the colony profile to enable the obtaining of the comparable optical signatures. The dedicated image processing algorithms were used for extraction of quantitative features of these signatures. The random forest algorithm was applied for selection of the most predictive set of features, which were used in classification model based on Support-Vector Machine. Obtained results have shown that the use of multiple multispectral optical signatures provide a multi-parametric bacteria identification at an exceptionally high accuracy (99.4-100%), significantly better than in case of classification based on each of these signatures (multispectral diffraction patterns, two-dimensional transmission coefficient maps), separately. Obtained results revealed that analysis of multispectral signatures can also be applied for characterisation of physical, physicochemical and chemical properties of the bacterial colonies in the presence of the antimicrobial factors. Therefore, the proposed label-free, non-destructive optical technique has perspectives to be exploited in the multipurpose diagnostics and it can be used as a pre-screening tool in microbiological laboratories.
新型诊断技术和方法的开发对于微生物污染的早期检测至关重要。在本研究中，展示了一种用于细菌菌落多参数光学表型分析和表征的新型集成系统。该系统将马赫-曾德尔干涉仪与光谱成像系统相结合，用于捕获细菌菌落的多光谱衍射图案和多光谱二维透射图，同时进行干涉轮廓测量。本研究对五种代表性细菌物种进行了研究，并记录了近3000个多光谱光学特征。通过四步相移算法分析干涉图以重建菌落轮廓，从而能够获得可比较的光学特征。使用专用的图像处理算法来提取这些特征的定量特征。应用随机森林算法选择最具预测性的特征集，并将其用于基于支持向量机的分类模型中。获得的结果表明，使用多个多光谱光学特征能够以极高的准确率（99.4 - 100%）进行多参数细菌鉴定，显著优于单独基于这些特征（多光谱衍射图案、二维透射系数图）进行分类的情况。获得的结果还表明，在存在抗菌因子的情况下，多光谱特征分析也可用于表征细菌菌落的物理、物理化学和化学性质。因此，所提出的无标记、非破坏性光学技术有望在多用途诊断中得到应用，并且可作为微生物实验室的预筛选工具。
